Details emerge on alleged plot to bomb airliners

LONDON - British authorities said Thursday they thwarted a terrorist plot to simultaneously blow up 10 aircraft heading to the U.S. using explosives smuggled in hand luggage, averting what police described as “mass murder on an unimaginable scale.”

Officials told NBC News that the alleged mastermind of the plot is still in Pakistan and has yet to be captured.

Some plotters had already purchased tickets on a flight to stage a test run planned for this weekend. The test run would have determined how easily the plotters could have gotten their materials past security and on board the planes.

The actual attack would have followed within days, officials told NBC News.

Police arrested 24 people saying they were confident they captured the main suspects in what U.S. officials said was a plot in its final phases that had all the earmarks of an al-Qaida operation. However, ABC News quoted unidentified U.S. officials who had been briefed on the plot as saying five suspects were still at large and being urgently hunted.

President Bush called the plot a “stark reminder” of the continued threat to the United States from extremist Muslims.

Senior U.S. intelligence officials told NBC News that the plot was on British officials’ radar for about two weeks and that several of the people involved had been monitored for several months when this plot came into view.

Asked whether there were a significant number of suspects involved in the plot still on the loose who could still carry out an attack, the official said, “They didn't get them all.”

Secretary of Homeland Security Michael Chertoff described the plot on Thursday as “well-advanced and well-thought-out and ... really resourced to succeed.”

The alleged plan
Britain disclosed no details about the plot or those arrested, although one police official indicated the people in custody were British residents, most of whom lived in east London. A French official in contact with British authorities described the arrested as originating from predominantly Muslim Pakistan.

British authorities said the suspects were arrested in London, its suburbs and Birmingham following a lengthy investigation, including the alleged “main players” in the plot.

At least one of the plotters attended a terrorist training camp in Pakistan, and more than one of the accused prepared a martyrdom tape, a counterterrorism official told NBC News.

Investigators say the plotters had not decided on specific flights to attack, but within the past few days were clicking around the Internet, looking at non-stop flights from the U.K. to the U.S. that left around the same time, NBC News’ Pete Williams reported.

U.S. officials say British investigators had the terror cell under close surveillance for several months, keeping the U.S. informed, then adding more specifics just within the past several days.

For the past several days, the FBI has feverishly looked for any potential ties to terrorists in the U.S., but has not found any.

“We literally in the last couple of weeks have had hundreds of FBI agents around the country tracking down every lead, and we have not found to date any plotters here in the United States,” FBI Director Robert Mueller told NBC.

Aviation experts say airport screening devices have a hard time picking up the chemicals the plotters planned to use, something officials verified with a test Thursday morning at Washington's Ronald Reagan National Airport.

Officials raised security to its highest level in Britain — suggesting a terrorist attack might be imminent — and banned carry-on luggage on all flights. Huge crowds backed up at security barriers at London’s Heathrow Airport as officials searching for explosives barred nearly every form of liquid outside of baby formula.

Chertoff said the terrorists planned to use liquid explosives disguised as beverages and other common products and set them off with detonators disguised as electronic devices.

“I can’t tell you that the particular explosives they had designed would have succeeded in bringing the planes down, but certainly you don’t even want to come close to taking that kind of a risk,” Chertoff said on MSNBC TV’s “Hardball.”

A counterterrorism official with knowledge of the plot and Thursday’s arrests told NBC News that the plotters, who ranged in age from 17 to 35, planned to use false-bottomed sports drink bottles to bring the liquids on board.

The terrorists on each plane would combine the separated liquids mid-flight to create an explosive solution.

An American law enforcement official who was briefed on the investigation said it appeared the liquid to be used was a “peroxide-based solution” to be detonated by an electronic device that was not specified, but could be anything from a disposable camera to a portable digital music player.

The official spoke on condition of anonymity because British authorities had asked that no information be released.

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